A dental implant (hereinafter simply referred to “implant”) used for implant treatment is made up of a fixture (implant body, for example, made of titanium) to be embedded into an alveolar bone at which a tooth is missing, an abutment coupled to and supporting the fixture, and a superstructure (artificial tooth crown) attached to the abutment. In the implant treatment that uses this type of implant, it is very important to accurately forming a guide hole, into which the fixture is to be embedded, in the alveolar bone (see JP-A-2001-170080, for example).
Implant treatment can be categorized into two types: prosthetically oriented treatment (top-down treatment) and exist-bone orientated treatment. In the former, prosthetically oriented treatment, a mockup (full-scale plaster model) of teeth and alveolar ridges of a patient is created. The mockup is mounted to an articulator in order to determine the geometries and position of a functionally and aesthetically ideal prosthesis (superstructure). Based on the determination, the position at which the fixture is to be embedded is decided. In the latter, exist-bone orientated treatment, the position that is surgically and anatomically ideal for the fixture to be embedded at is determined based on the condition of the alveolar bone (the width, thickness, and density of the alveolar bone, the course of the nerve, or other factors) of a patient.
Currently, simulation software in which CT (computed tomography apparatus) or other apparatus is utilized may be used for determining the position that is prosthetically (functionally and aesthetically) ideal for the fixture to be embedded at, in consideration of the condition of the alveolar bone or other factors of the patient. In addition, a stent that contains a contrast medium may be used in CT scanning in order to display onto the mockup the position that is determined on a CT display as a position the fixture is to be embedded at.
When a guide holeinto which a fixture is to be embedded is drilled in an alveolar bone of a patient, three-dimensional positioning of the drill in the mouth of the patient is required. However, it is quite difficult to accurately form a guide hole by freehand at the position the fixture should be embedded while looking at the CT display or the mockup. Therefore, various jigs, i.e., surgical guides, have been devised.
A typical example is a surgical guide that has a metallic guide ring for guiding a drill to the position at which the fixture should be embedded. When a drill is placed into a hole in the guide ring and inserted along the hole in the guide ring, the drill is guided such that a guide hole is formed at the position the fixture should be embedded.